The Philippine Agricultural Scientist

Publication Date



This study aimed to describe the effects of Salmonella Typhimurium flagellin (SFL) dephosphorylated by sweet potato purple acid phosphatase (PAP) on the protective responses of the intestinal epithelial cell line HT-29 cells. The enzyme was reported to display a broad substrate specificity for various organic phosphorylated conjugates and phosphoproteins. Dephosphorylation of SFL by sweet potato PAP decreased to 35% in the presence of 0.05 mM vanadate as compared with the negative control (p < 0.05). Intact SFL and the SFL treated with sweet potato PAP did not remarkably induce the activation of caspase-3 in HT-29 cells at all the tested levels of the substrate. Intact SFL maximally induced the release of IL (interleukin)-8 in HT-29 cells at 1000 ng/mL (p < 0.05). However, the SFL treated with the enzyme inhibited the release of IL-8 at over 100 ng/mL of the substrate as compared with intact SFL, resulting in an approximately 8-fold decrease even at 1000 ng/mL (p < 0.05). The SFL treated with the enzyme decreased the activation of the total ERK1/2 in the cells to 1.9 and 1.7–fold at 10 and 1000 ng/mL of the substrate, respectively, as compared with intact SFL (p < 0.05). In conclusion, sweet potato PAP could be a promising tool for controlling excessive inflammation during Salmonella infection in animal husbandry, and the enzyme could be a safe alternative that can overcome the drawbacks of chemotherapy.



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